Among polyurethane foams, shape memory polyurethane foams and low repulsion polyurethane foams are already known. However, the dynamic viscoelasticity of these polyurethane foams when worn on the human body had previously not been investigated. When worn on the human body, the energy absorption capability of these foams is poor, and they suffered from poor wearable comfort.
In contrast, Patent Literature 1 (PTL 1) discloses a resin foam having good shape-following properties, which undergoes a reduction in hardness upon heat transfer from the human body, enabling the foam to deform and follow the shape of the surface of the body. The resin foam of PTL 1 is composed, for example, of a polyurethane foam, which has a glass transition point of 10 to 35° C. (namely, in the vicinity of the body surface temperature), and exhibits a loss tangent tan δ within this temperature range of 0.20 to 0.80.